The Internet comprises a vast number of computers and computer networks that are interconnected through communication links, with access to information being provided using various services such as electronic mail (“email”) and the World Wide Web (also referred to as the “Web”). In addition to providing access to information, the Web has increasingly become a medium that is used to search for, shop for and order items (such as products, services and/or information) that are for purchase, rent, lease, license, trade, evaluation, sampling, subscription to, etc. In many circumstances, a user can visit the Web site of a Web merchant (or a “Web store”) or otherwise interact with an online retailer or electronic marketplace that provides one or more items, such as to view information about the items, give an instruction to place an order for one or more items, and provide information needed to complete the purchase (e.g., payment and shipping information). The Web merchant then fulfills the order by providing the ordered items to the indicated recipient, such as by providing product items that have been ordered through physical distribution channels (e.g., shipment via a governmental postal service or private common carrier) or electronically (e.g., via download over the Internet, such as for digital music or videos) as appropriate. Ordered service items may similarly be provided electronically (e.g., providing email service) or physically (e.g., performing cleaning services at the purchaser's house).
Some Web sites have arisen that allow users to sell items to and purchase items from each other, such as DVD movies, audio CDs, or video games. A user will typically register to become a customer by entering personal information, such as the user's name, mailing address and payment information. Once registered, the customer can interact with other customers to provide or receive items. For example, a customer may be able to specify items that (s)he would like to receive from others and/or items that (s)he is willing to provide to others. When a match between two customers is made for a particular item, the customer who has the item provides it to the other customer who would like to receive it, typically based on some form of compensation given to the customer providing the item (e.g., monetary payment, “points” or other form of credit tracked by the Web site, etc.). Similarly, the customer who receives an item typically provides some form of compensation for receiving the item. The operator of such a Web site may in some cases obtain revenue in various ways, such as by charging a fee for each item transaction, by charging a fee for membership, etc.
However, various problems exist with such Web sites for facilitating transactions involving items and users. One such problem results from difficulties in appropriately balancing user supply and demand for items. For example, if several users each desire a copy of an item that is available from a large number of other users, such Web sites typically have difficulties in ensuring that the users who desire the item each receive a copy in a timely manner without notifying an excess number of the users who have the available item copies. If too few of the users who have the available item copies are notified (or if the notified users do not respond in a timely manner), then insufficient copies of the item will be supplied for the users who desire item copies, resulting in customer dissatisfaction among the users who do not receive items. Conversely, if too many of the users who have the available item copies are notified (e.g., all of them), many of the notified users will be unable to actually supply their item copies in response to the notification because other notified users have already met the demand for the item, resulting in customer dissatisfaction among those users.
Thus, it would be beneficial to provide techniques to facilitate transactions involving items and users, as well as to provide other benefits.